Why say "...workers who had this, or who that..." instead of "...workers who had this, and those who had that..."?

Question

I wrote the following sentence:

1. Regionally differentiating weekly EI benefits affects workers who had shorter work periods, and those who had inconsistent weekly earnings prior to their layoff (AuthorName Year).

This means that regionally differentiating weekly EI benefits affects two groups of workers:

• (a) workers who had shorter work periods prior to their layoff

• (b) workers who had inconsistent weekly earnings prior to their layoff

So it affects workers who are only in (a), or only in (b), or in both (a) and (b).

I am told that no.1 is correct, but that many or most native speakers would automatically prefer no.2 (below).

2. Regionally differentiating weekly EI benefits affects workers who had shorter work periods, or who had inconsistent weekly earnings prior to their layoff (AuthorName Year).

To me, "workers who had ..., and those who had" is equivalent to "workers who had ..., or who had".

I don't see how no1. could be possibly misconstrued as saying

"...affects workers who had [both] shorter work periods and inconsistent weekly earnings".

Question: I just want to know why no.2 would be preferred over no.1 when they are both saying the same thing. Why? I don't think many or most native speakers choosing no.2 is a matter of style/choice. There has to be a reason; I can't quite figure that out yet.

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I will probably get flagged "duplicate" for this. I have gone through other "and/or" questions in ELL but I can't find anything that solves my problem. It is possible that I might have missed the right one.

Answer 1

Logically you are correct, the conditions specified in the two versions of the sentence are exactly the same, and no one reading the sentence with attention could be confused about that.

Version 1 could, on a skimming or careless read, seem to apply to two separate groups, and indeed the affected workers could be thought of as being two separate groups, who may well overlap. Sentence 2 emphasizes that there is one group, defined by a complex condition: "either this or that". That is a purely stylistic difference. Version 2 is also slightly shorter as measured by syllable count.

I don't know that I would agree that most native or fluent speakers would prefer 2. Some would no doubt. But without a poll on this specif question, who can say with assurance. 1 does not feel off or awkward to this native speaker, but neither does 2.